ArCH₂⁺: A Detectable Noble Gas Molecule

Abstract

The noble gas molecular cation, ArCH2+, has been observed in mass spectrometry experiments, and the present work is providing high‐level quantum chemical predictions for the vibrational and rotational spectroscopic data necessary to observe this molecule in situ in other laboratory conditions. The Ar−C stretch in this cation is a bright fundamental vibrational frequency that should be observable in the early regions of the far‐infrared at 421.2 cm−1 for the universally most common 36Ar isotope. The near‐prolate nature of this molecule and its 2.91 D dipole moment should also make it distinguishable for submillimeter detection, as well. Furthermore, the Ar−C bond strength in ArCH2+ is greater than the global minimum for the dissociation of the experimentally known ArOH+ cation. As a result, the infrared spectrum of this simple organo‐noble gas molecule is likely waiting to be observed and may already exist in the spectra of hydrocarbon cations in argon‐matrix condensed phase experiments.

Noble-Gas Chemistry More than Half a Century after the First Report of the Noble-Gas Compound

“…Another story is the number of reported charged species detected in the gas phase. Some recent examples include observation of ArCH 2 + in mass spectrometry experiments [ 53 ] and the production of ArOH + molecular ion in a pulsed discharge/supersonic expansion of argon seeded with water vapor [ 54 ]. The cation complexes [ArB 3 O 4 ] + , [ArB 3 O 5 ] + , [ArB 4 O 6 ] + , and [ArB 5 O 7 ] + were prepared via laser vaporization supersonic ion source in the gas phase [ 55 ].…”

Theoretical investigation on the structure and stability of some neutral noble gas compounds containing Xe‐Xe bond

“…Although just limited noble gas molecules have been synthesized experimentally, many types of noble gas compounds are possible from theoretical point of view . This list includes compounds which have been also observed experimentally; such as XeF 6 , KrF 2 , HArF, clathrates and clathrate hydrates, coordination compounds, hydrates (Xe.6H 2 O), HeH + , oxyfluorides (XeOF 2 , XeOF 4 , Xe 2 O 3 F 2 , XeO 2 F 4 ), and fullerene compounds.…”